1. Field Of The Invention
This invention relates generally to a surgical instrument and its assembly and more particularly concerns a surgical instrument used for removing particles and fluid from an eye during cataract surgery while also infusing replacement fluid.
2. Brief Description Of The Prior Art
Cataract surgery on the human eye requires, in part, that the eye lens capsule be cleaned of particles. This task is accomplished by aspirating particulate-laden fluid from the interior of the eye and replacing it with clean fluid. It is necessary to perform the aspiration and infusion of fluid simultaneously in order to maintain appropriate internal pressure and volume of the lens cavity.
Such a fluid exchange is typically performed by a small, hand-held probe which is inserted in the eye through an incision, and which includes two rigid transfer tubes, one tube for fluid removal and the other for fluid infusion. These two transfer tubes are connected to two fluid supply tubes, one of which provides infusion fluid, and the other is connected to a vacuum source. Many prior art ophthalmic probes for infusing and aspirating fluid utilize a concentric tube configuration.
Precision manufacturing and assembly of such instruments are expensive, and a probe with several complex parts is likely to be costly. Conventional probes, for example, ordinarily use specially shaped ducting components to perform the function of directing fluid flow from two side-by-side tubes into a probe tip having a concentric tube flow configuration. Martinez, U.S. Pat. No. 4,652,255 is exemplary, disclosing a device where infusion fluid is routed from a side tube into an annular reservoir in the handle from where it flows through a concentric tube to the eye. The Martinez device includes several small and rigid components which must be precision manufactured in order to meet the demands of ophthalmic surgery.
It is desirable in such a probe to prevent the warming of the infusion fluid, because lower fluid temperature minimizes the chance of illumination light damage to the eye during the procedure. Advanced technology surgery systems cool the fluid for this reason. Yet some ophthalmic probes leave the flow tubes exposed, susceptible to contact with a surgeon's hand during the procedure. See for example, Grandon, U.S. Pat. No. 4,578,058. Other probes disclosed in the prior art provide a handle which encloses the tubes; however, there is no disclosure of any means specifically to insulate the infusing fluid. See for example, Woods, U.S. Pat. No. 4,652,255, and Reimels, U.S. Pat. No. 4,705,500, which disclose solid handles in direct contact with the tubes.
In the Martinez device, where the handle body doubles as fluid reservoir, the fluid flows through a cavity formed by the housing and is then infused into the eye through a concentric channel. With this design, the relatively large quantity of fluid in the handle adds weight and subjects the fluid to warming by the surgeon's hand.
Although these prior teachings show that a hand-held ophthalmic infusion/aspiration probe is effective when comprised of concentric tubes, none addresses the problem of keeping the fluid cool while also maintaining light weight and low cost by the use of few, simple components.
In accordance with the foregoing, it is a general object of this invention to provide a improved fluid infusion and aspiration probe for use in removing particles from the eye during cataract surgery.
A related object is to provide such a surgical probe which has relatively few parts, is simple in design, and is inexpensive to manufacture.
A more specific object of the invention is to provide a simple and effective method of connecting two separate supply tubes to the separate concentric fluid transfer channels of such a probe.
Another object of the invention is to provide an infusion/aspiration probe which will hold only a small amount of fluid, thereby being lightweight and responsive.
Another object of the invention is to provide a surgical instrument which insulates the infusing eye fluid from the warming effects of a surgeon's hand.
It is a further object of the invention to provide a simple and effective means to relatively fix two concentric tubes of a surgical instrument.
Other objects and advantages of the present invention will be apparent to those skilled in this art from the following description and the appended claims.